1. Field of the Invention
A suspended air purifier light fixture of very low profile suitable for ceiling mounting in conference rooms or open plan offices and public areas. The fixture simultaneously provides effective removal of tobacco smoke and other indoor pollutants while serving as a conventional light fixture. The fixture is quiet in operation, has a low profile, provides for the efficient flow of air, has a simple visual appearance and does not require modification of the ceiling construction.
2. Description of the Prior Art
The growing evidence supporting the deleterious effect of tabacco smoke has brought the problem of indoor air pollution into sharp focus. People are now conscious of the fact that indoor sources of pollutants, such as secondary cigarette smoke and the outgassing of modern building materials, are potentially as harmful to health as the actual smoking of cigarettes. Many states and communities have enacted laws and ordinances governing smoking in public places and workplaces. However, such laws and ordinances are often difficult to enforce, do not cover all localities and conditions, and may not apply to less well-known, but still dangerous sources of pollution. Thus, there is a growing need and demand for methods of and mechanical devices for removing indoor air pollutants, specifically, offensive cigarette smoke which ideally should be captured as close to the source as possible before the smoke mixes with the surrounding air.
In order to capture the pollutants, special attention must be paid to the configuration of any mechanical device used for this purpose and additionally the influence of the exhaust air flow pattern from the mechanical device must be carefully controlled. These purposes are best accomplished by a substantial reduction of exhaust air velocity in accordance with dispersion means and the geometry of the device. Where smoke removal is concerned, a poorly located exhaust air grille and excessive exhaust flow velocity through that grille has two main undesirable characteristics. First, the exhaust air can actually blow the smoke away before it reaches the intake. Second, high exhaust velocity generates a Bernoulli effect, thereby generating a region of negative pressure outside of the device to them compete with the negative pressure at the intake of the device. Obviously smoke attracted to the exhaust region is then blown away by the exhaust. In addition, when an exhaust grille is located too near the intake grille, "short circuiting" can occur, where the device intakes much of its own exhaust rather than ambient air.
Air purification equipment may be integrated within the building air handling system. If not incorporated at construction time, which is often the case, retrofit can be costly in labor and materials. Existing stand-alone devices are bulky and not designed to be simply hung in a space and switched on. A significant installation effort may be required, if only to conceal the unit behind suspended ceilings. Typical applications for stand-alone suspended air purifiers are in indoor, confined public spaces such as restaurants and bars where people congregate and often smoke. Offices, and particularly, conference rooms, or conference areas, are also examples of workspaces where cigarette smoking in groups may be a problem. Enclosed office areas also concentrate other indoor pollutants such as formaldehyde, bacteria and dust, especially in new buildings without operable windows.
The above described problem areas also are typically illuminated by suspended lighting fixtures which usually provide a significant amount of ambient light. Air purifiers and light fixtures, therefore, may both be directly suspended overhead for optimum operation and would be competing for the same overhead installation space. This additional problem suggests the appropriateness of a combination light source and air purifier, especially for use in a small converence area within an enclosed room or in an open-plan office, or in any other small scale spaces such as bars or workrooms.
Available filtration technology falls generally into two categories. Thse are electrostatic precipitation and filtration media, both of which have relative advantages an disadvantages. The actual method of filtration is not a specific part of the present application invention, since either or both techniques may be used. However, where is is relevant, a particular technique will be mentioned in more detail in the present application.